Description
Introduction
Planting a vegetable garden can supply you, your family, and your community with an abundance of fresh, healthy vegetables throughout the season. When properly done, gardening can also beautify your landscape, protect water quality, and conserve natural resources. Environmentally-sound gardening approaches will minimize the amount of purchased fertilizers you need by improving soil fertility through crop rotation and turning waste materials into valuable compost and fertilizer. Additional motivations for starting a vegetable garden include growing crops that are not commonly found in the stores or specialty markets in your area and experimenting with vegetables that are unfamiliar to you. Some examples of foods to explore with your family are shallots, edamame, corn salad, and fennel.
Vegetable Garden Considerations
To be a successful vegetable gardener there are many considerations and choices you will need to make. Experiment each year to find the crops and techniques that best suit you and your garden site.
Site-Specific Growing Conditions
Convenience is important as you select a vegetable garden site, but full sun exposure and suitable soil are more important. Most vegetable crops require at least six hours of direct sunlight each day, so locate your garden for maximum exposure to available sunlight. Also take into account that vegetables require fertile, well-drained soil. If you live in an area that receives heavy rainfall, soil drainage is especially important.
Soil drainage is determined mostly by the site but can be improved by using raised beds. Select a location with enough slope for surface drain-age and sufficient subsoil permeability to allow water to drain through. You can add fertilizers to improve soil fertility and use organic matter to improve soil structure. If you are in an area where soils may be contami-nated with heavy metals from heavy industry or old orchard practices, consult with your local Extension office or health department about how to conduct a soil test.
One of the most important factors to consider when selecting vegetable crops to grow in your garden is climate. Climate includes length of growing season (Figure 1A), first and last frost dates (Figures 1B and 1C), as well as temperatures during the season. The USDA plant hardiness zone map (Figure 2) provides information regarding extreme minimum temperatures for Washington.
Vegetables are generally divided into warm-season (summer) crops and cool-season (fall/winter/spring) crops (Table 1). Many warm-season vegetable crops require a longer growing season or warmer temperatures than are available west of the Cascade Mountains. In areas where temperature is limiting, row covers and plastic tunnels may be used to successfully grow these crops. Many cool-season crops can be grown throughout the winter in areas west of the Cascades, depending on the microclimate.
Table 1. Crops well-suited to warm and cool temperatures in Washington (adapted from Maynard and Hochmuth 1997, 89).
Warm-Temperature Crops
- Bean
- Corn, Sweet
- Cucumber
- Edamame
- Eggplant
- Melon
- New Zealand Spinach
- Okra
- Pepper
- Pumpkin
- Squash, Summer
- Squash, Winter
- Sweet Potato
- Tomato
Eggplant, Okra, and Sweet Potato crops require the most warmth to be productive; in cooler areas they will need to be grown in plastic covered tunnels or greenhouses.
Cool-Temperature Crops
- Artichoke
- Artichoke, Globe
- Asparagus
- Bean, Broad
- Beet
- Broccoli
- Brussels Sprout
- Cabbage
- Carrot
- Cauliflower
- Celery
- Chard, Swiss
- Chicory (Endive)
- Chive
- Collards
- Garlic
- Horseradish
- Kale
- Kohlrabi
- Leek
- Lettuce
- Mustard
- Onion
- Parsley
- Parsnip
- Pea
- Potato
- Radish
- Rhubarb
- Salsify
- Spinach
- Turnip
Artichoke, Globe Artichoke, Asparagus, Horseradish, and Rhubarb crops are perennial.
Figure 1. Washington climate factors affecting vegetable production: length of growing season (frost-free days) (A); average last killing frost date in spring (B); and average first killing frost date in fall (C) (adapted from Antonelli et al. 2004, 4).
The image is a color‑coded USDA Plant Hardiness Zone Map of Washington State. The title at the top reads “USDA Plant Hardiness Zone Map – Washington.” The map depicts average annual extreme minimum temperatures for the period 1976–2005 and categorizes the state into plant hardiness zones based on temperature ranges.
Washington State is shown with county boundaries, major cities, rivers, and regional labels. A legend appears on the left side of the map showing hardiness zones labeled 4a through 9a, each associated with a temperature range in both degrees Fahrenheit and Celsius. Cooler temperature zones are represented by shades of purple and blue, while warmer zones are shown in greens, yellows, and orange tones.
Western Washington, including the Olympic Peninsula, Puget Sound region, and coastal areas, is primarily shown in yellow and light green shades representing zones 7a, 7b, and 8a, with some areas reaching zone 8b near the coast and in urbanized regions around Seattle, Tacoma, Olympia, and Everett. The Olympic Peninsula and coastal counties such as Clallam, Jefferson, Grays Harbor, and Pacific are mostly in zone 7a to 8a.
The Puget Sound region, including cities such as Seattle, Tacoma, Everett, and Olympia, is mostly in zones 7b and 8a. Island County and San Juan County are also shown in relatively mild zones compared to surrounding inland areas.
Central Washington transitions to cooler zones shown in shades of green. Areas including Chelan, Douglas, Kittitas, Grant, Yakima, and Benton counties range mainly from zones 6a to 7a. The Cascade Mountain range is visible as a north–south band of cooler zones separating western and eastern Washington.
Eastern Washington varies by region. The Columbia Basin and southeastern counties, including Franklin, Walla Walla, Columbia, and Adams counties, are shown primarily in zones 6b to 7a. Northeastern Washington, including Ferry, Stevens, Pend Oreille, and parts of Spokane County, is shown in cooler zones, generally 5a to 6b, indicating lower average minimum winter temperatures.
Major rivers such as the Columbia River and Snake River are drawn and labeled. The Columbia River runs along parts of the southern and central regions of the state and forms part of the boundary with Oregon. The Snake River appears in the southeastern corner near the borders with Idaho and Oregon.
Major cities including Spokane, Wenatchee, Yakima, Pasco, Walla Walla, Vancouver, Bellingham, and Port Angeles are labeled for geographic reference. County names are printed across the map in white or black text for contrast.
At the bottom right of the image, scale bars indicate distance in both miles and kilometers. Logos for the USDA Agricultural Research Service and Oregon State University’s PRISM Climate Group appear in the lower left corner, indicating the data sources used to create the map.
Overall, the map visually communicates that western Washington has milder winter minimum temperatures suitable for warmer hardiness zones, while eastern and mountainous regions experience colder extremes and lower hardiness zones.
The wide assortment of vegetable plants that are commercially available have been selected for their performance under “normal” garden conditions, but in order to get the best results for your garden, you should also consider your specific microclimate and growing conditions. For example, the cool springs in western Washington can make it difficult to get good germination of crops that prefer warm soils. Refer to Gardening in the Inland Northwest (Fitzgerald 2001, MISC0304) for detailed growing guidelines suited to that area.
Crop Selection
What you decide to grow in your vegetable garden depends on what you want from it. For example, you can trim your food budget by growing the more expensive vegetables that your family normally eats. Tomatoes, summer squash, and peppers usually cost more per pound in the store than other vegetables. Yet these crops can be productive in home gardens and require less space to grow than potatoes, cabbage, and winter squash which cost much less per pound.
Some vegetables such as tomatoes, sweet corn, and peas have better flavor and quality when they are picked at their prime maturity and prepared immediately after harvest. Other vegetables such as cabbage, potatoes, and onions can be left in the garden for several weeks after they reach harvestable size with little loss in flavor or texture. If your purpose is to grow vegetables that taste better than what you can buy at the grocery store, concentrate on those that benefit most from immediate use after harvest. Table 2 compares the relative quality, productivity, and monetary values of commonly-grown vegetables.
Table 2. Differences in quality, production, and value between common home-grown and store-bought vegetables in Washington (adapted from Antonelli et al. 2004, 3).| Vegetable | Garden & Store Difference in Quality | Production per Square Foot | Relative Monetary Value |
|---|---|---|---|
| Asparagus | high (this home-grown vegetable is far superior to the store-bought version) | medium | high |
| Bean, Green | medium (this home-grown vegetable is somewhat superior to the store-bought version) | high | medium |
| Beet | medium | high | medium |
| Bok Choy | low (there is little difference between the home-grown and store-bought versions) | medium | medium |
| Broccoli | medium | high | high |
| Brussels Sprout | medium | low | high |
| Cabbage | low | low | low |
| Carrot | medium | high | medium |
| Cauliflower | low | medium | high |
| Celery | low | medium | medium |
| Chard, Swiss | high | high | medium |
| Collards | medium | medium | high |
| Corn, Sweet | high | low | low |
| Cucumber | medium | medium | high |
| Edamame | high | medium | high |
| Eggplant | medium | low | high |
| Kale | medium | high | high |
| Kohlrabi | low | medium | medium |
| Leek | medium | medium | high |
| Lettuce, Leaf | medium | medium | high |
| Lettuce, Head | low | low | medium |
| Muskmelon (Cantaloupe) | low | low | medium |
| Onion, Bulb | low | medium | low |
| Onion, Green | high | high | high |
| Parsnip | low | medium | medium |
| Pea | high | medium | high |
| Pepper | medium | low | high |
| Potato | low | medium | low |
| Pumpkin | low | low | low |
| Radish | low | high | medium |
| Rhubarb | medium | high | high |
| Spinach | medium | medium | medium |
| Squash, Summer | high | high | high |
| Squash, Winter | low | medium | low |
| Tomato | high | medium | high |
| Turnip | low | high | medium |
| Watermelon | low | low | low |
To obtain fresh food from your vegetable garden throughout the season, make small plantings of each crop two to four times during the season so they mature in manageable quantities over time. If your intent is to can, dry, or freeze vegetables to eat later in the year, plant in large blocks so each crop is ready for processing at one time. Some vegetables such as winter squash, potatoes, and onions can be kept for several weeks or even months in a cool, dry storage room, such as a garage. Table 3 provides a guide for how many pounds of vegetables the average adult consumes in one year, both fresh and processed. Use this information to help you decide how much to plant of each crop for your household.
